Hepatitis B virus and other transfusion-transmissible infections in child blood recipients in Lao People's Democratic Republic: a hospital-based study.

INTRODUCTION: Children requiring multiple blood transfusions are at high risk of transfusion-transmissible infections (TTIs). Lao People's Democratic Republic is a low-resource setting where donor blood screening faces challenges. This study aimed to determine the burden of TTIs in children in Vientiane Capital. METHODS: 300 children with transfusion history and 300 controls were recruited. In addition, 49 newly diagnosed transfusion recipients were followed for up to 12 months. Serum was tested for hepatitis B surface antigen and IgG antibodies against parvovirus B19, hepatitis B, C and E viruses. RESULTS: The patients had a similar prevalence of anti-hepatitis B core antibodies (56; 18.7%) and hepatitis B surface antigen (8; 2.7%) as the controls (58; 19.3% and 9; 3.0%, respectively). However, there was a higher prevalence of an antibody profile suggestive of hepatitis B vaccination (anti-hepatitis B surface antibody positive/anti-hepatitis B core antibody negative) in the transfused group (140/299; 46.8%) than in controls (77/300; 25.7%, p<0.01). All other markers were similar in the patients and controls or higher in the controls: anti-hepatitis C virus (2.7% and 3.3%, p=0.6), anti-hepatitis E virus (7.5% and 12.7%, p=0.006) and anti-parvovirus B19 (2.4% and 8.5%, p=0.001). The longitudinal cohort did not show an increase in any marker over time. CONCLUSION: Our results suggest no significant role of TTIs in Lao children. The higher prevalence of the hepatitis B vaccination profile in transfusion recipients showed that recommendations to vaccinate before commencing transfusions is at least partially implemented, although there is room for improvement.

ß-Hemoglobinopathies in the Lao People's Democratic Republic: Molecular diagnostics and implication for a prevention and control program.

INTRODUCTION: A high frequency of ß-thalassemia in Lao People's Democratic Republic necessitates the importance of complete molecular data before a prevention and control program could be established. Limited data are available for Lao PDR. We have now reported an extended information on the molecular basis of ß-hemoglobinopathies in this population. METHODS: The study was done on 519 unrelated Laos subjects requested for thalassemia investigation. Hematological data were recorded. Hb profiles were obtained using a capillary electrophoresis system. α-And ß-globin genotyping was performed using PCR and related techniques. RESULTS: Among the 519 subjects, 287 (55.3%) were found to carry ß-hemoglobinopathies based on Hb and DNA analyses. These included Hb E carriers (n = 135), homozygous Hb E (n = 47), ß-thalassemia carriers (n = 70), Hb E-ß-thalassemia (n = 25), homozygous ß-thalassemia (n = 4), heterozygous δß0 -thalassemia (n = 2), and carriers of the ß-Hb variant (n = 3). Mutation analysis identified in addition to the Hb E, 8 different ß-thalassemia mutations including codon 17 (A-T), codons 41/42 (-TTCT), NT-28 (A-G), codons 71/72 (+A), IVS1-1 (G-T), 3.4 kb deletion, an initiation codon (T-G) and IVS2-654 (C-T). Two δß0 -thalassemia carriers (12.6 kb deletion) and three subjects with Hb Hope (ß136GGT-GAT ) were identified. Hematological features associated with these ß-hemoglobinopathies were presented. CONCLUSION: ß-hemoglobinopathies in the Laos population is heterogeneous. This information is relevant for setting up a molecular diagnostics and can provide a basis for genetic counseling and enable prenatal diagnosis.